A bead ring winding machine of this type is disclosed, for example, in Patent Document 1. In this conventional structure, an annular recessed part used for winding a wire in rows and in tiers is formed in the outer circumferential surface of a circular bead former rotatable about a shaft. The inner bottom portion of the recessed part is provided with multiple alignment grooves in which turns of the wire in the innermost circumference are guided and aligned at regular intervals.
The alignment grooves described in Patent Document 1 include a circumferential groove in which the wire is wound substantially one turn in the circumferential direction of the bead former and an oblique groove formed between adjacent circumferential grooves. The oblique groove is used to guide the wire wound in one circumferential groove to a next circumferential groove. Patent Document 1 further discloses an alignment groove formed in a spiral pattern. In this structure, the wire is wound in a spiral pattern on the bead former.
The alignment grooves of the bead ring winding machine of Patent Document 1 include the circumferential groove and the oblique groove. Thus, a winding orbit of the wire in the innermost circumference is changed forcibly in a short turning region of the oblique groove. However, the high stiffness of the wire makes it difficult to shift the wire to a next circumferential groove smoothly along the oblique groove. This may unfortunately result in an irregular winding condition. The structure of forming the alignment groove in a spiral pattern forms each of a side edge portion of the alignment groove where winding starts and a side edge portion of the alignment groove where the winding ends into a narrow width. This makes it impossible to align turns of the wire in the innermost circumference in a position where winding starts and in a position where the winding ends. This may unfortunately result in an irregular winding condition, so that the wire wound outside the wire in the innermost circumference may collapse easily. Such collapse of winding of the wire in the innermost circumference causes an unstable inner circumferential length of a bead ring. Further, winding the entire wire in a spiral pattern places the wire in a direction tilted to the axis line of the bead ring. This may cause an unstable inner circumferential length of the bead ring or place the wire at a tilt. This may unfortunately damage the grasping function of a tire bead part as a function inherent to the bead ring.